Search

Gaultheria nummularioides D.Don 1825 (Ericaceae) is a traditional Chinese medicinal plant used to treat rheumatoid arthritis. The complete chloroplast genome of G. nummularioides has been sequenced and assembled. The genome is 176,207 bp in total with one large single copy (LSC: 107,726 bp), one small single copy (SSC: 3,389 bp), and two inverted repeat regions (IRa and IRb; each 32,546 bp). The chloroplast genome encoded a total of 110 unique genes; the GC content of these genes is 36.6%. The results based on phylogenetic analysis of the complete chloroplast genome suggests that G. nummularioides diverged later than G. praticola, the sister relationship between G. nummularioides and the clade comprising G. fragrantissima Wall. 1820 and G. hookeri C.B. Clarke 1882 was strongly supported. This study provides additional information on the genetic diversity of G. nummularioides, its closely related taxa, and further exploration of chloroplast genomes in the Ericaceae family.

Abstract Background Polypodiales suborder Dennstaedtiineae contain a single family Dennstaedtiaceae, eleven genera, and about 270 species, and include some groups that were previously placed in Dennstaedtiaceae, Hypolepidaceae, Monachosoraceae, and Pteridaceae. The classification and phylogenetic relationships among these eleven genera have been poorly understood. To explore the deep relationships within suborder Dennstaedtiineae and estimate the early diversification of this morphologically heterogeneous group, we analyzed complete plastomes of 57 samples representing all eleven genera of suborder Dennstaedtiineae using maximum likelihood and Bayesian inference. Results The phylogenetic relationships of all the lineages in the bracken fern family Dennstaedtiaceae were well resolved with strong support values. All six genera of Hypolepidoideae were recovered as forming a monophyletic group with full support, and Pteridium was fully supported as sister to all the other genera in Hypolepidoideae. Dennstaedtioideae (Dennstaedtia s.l.) fell into four clades with full support: the Microlepia clade, the northern Dennstaedtia clade, the Dennstaedtia globulifera clade, and the Dennstaedtia s.s. clade. Monachosorum was strongly resolved as sister to all the remaining genera of suborder Dennstaedtiineae. Based on the well resolved relationships among genera, the divergence between Monachosorum and other groups of suborder Dennstaedtiineae was estimated to have occurred in the Early Cretaceous, and all extant genera (and clades) in Dennstaedtiineae, were inferred to have diversified since the Late Oligocene. Conclusion This study supports reinstating a previously published family Monachosoraceae as a segregate from Dennstaedtiaceae, based on unique morphological evidence, the shady habitat, and the deep evolutionary divergence from its closest relatives.

Dryopteris sect. Diclisodon is a small section of ferns with about 12 species mainly distributed in East Asia. Here, we carried out morphological and phylogenetic analyses of this section. A new species from southwest China, D. gaoligongensis, is described and illustrated. Dryopteris gaoligongensis resembles D. indonesiana and D. sparsa, but differs by having a creeping rhizome and large 4-pinnate fronds. We also show that D. glabrior Ching & Z.Y. Liu is a distinct species; however, because it is a later homonym of D. glabrior Copel., it should be renamed D. renchangiana. We conclude that a species previously known as D. nitidula, also an illegitimate homonym, should be recognized with a new name, D. sinonepalensis. We resolve the phylogenetic position of D. yoroii as sister to other sampled species of D. sect. Diclisodon. Our phylogenetic analyses confirm the distinctiveness of D. gaoligongensis, D. renchangiana, and D. sinonepalensis. A key to species of D. sect. Diclisodon in China is provided.

Structural variation of plastid genomes (plastomes), particularly large inversions and gene losses, can provide key evidence for the deep phylogeny of plants. In this study, we investigated the structural variation of fern plastomes in a phylogenetic context. A total of 127 plastomes representing all 50 recognized families and 11 orders of ferns were sampled, making it the most comprehensive plastomic analysis of fern lineages to date. The samples included 42 novel plastomes of 15 families with a focus on Hymenophyllales and Gleicheniales. We reconstructed a well-supported phylogeny of all extant fern families, detected significant structural synapomorphies, including 9 large inversions, 7 invert repeat region (IR) boundary shifts, 10 protein-coding gene losses, 7 tRNA gene losses or anticodon changes, and 19 codon indels (insertions or deletions) across the deep phylogeny of ferns, particularly on the backbone nodes. The newly identified inversion V5, together with the newly inferred expansion of the IR boundary R5, can be identified as a synapomorphy of a clade composed of Dipteridaceae, Matoniaceae, Schizaeales, and the core leptosporangiates, while a unique inversion V4, together with an expansion of the IR boundary R4, was verified as a synapomorphy of Gleicheniaceae. This structural evidence is in support of our phylogenetic inference, thus providing key insight into the paraphyly of Gleicheniales. The inversions of V5 and V7 together filled the crucial gap regarding how the “reversed” gene orientation in the IR region characterized by most extant ferns (Schizaeales and the core leptosporangiates) evolved from the inferred ancestral type as retained in Equisetales and Osmundales. The tRNA genes trnR-ACG and trnM-CAU were assumed to be relicts of the early-divergent fern lineages but intact in most Polypodiales, particularly in eupolypods; and the loss of the tRNA genes trnR-CCG, trnV-UAC, and trnR-UCU in fern plastomes was much more prevalent than previously thought. We also identified several codon indels in protein-coding genes within the core leptosporangiates, which may be identified as synapomorphies of specific families or higher ranks. This study provides an empirical case of integrating structural and sequence information of plastomes to resolve deep phylogeny of plants.

Gaultheria nummularioides D.Don 1825 (Ericaceae) is a traditional Chinese medicinal plant used to treat rheumatoid arthritis. The complete chloroplast genome of G. nummularioides has been sequenced and assembled. The genome is 176,207 bp in total with one large single copy (LSC: 107,726 bp), one small single copy (SSC: 3,389 bp), and two inverted repeat regions (IRa and IRb; each 32,546 bp). The chloroplast genome encoded a total of 110 unique genes; the GC content of these genes is 36.6%. The results based on phylogenetic analysis confirmed that G. nummularioides diverged later than G. praticola, and the sister-group relationship between G. nummularioides and the clade comprising G. fragrantissima Wall. 1820 and G. hookeri C.B.Clarke 1882 was strongly supported, revealing the phylogenetic position of G. nummularioides. This work provides additional information for studying the genetic diversity of G. nummularioides and its closely related taxa, as well as further exploration of chloroplast genomes in the Ericaceae family.

With the advantages of high energy density, long cycle life and high stability, lithium-ion batteries have been used in a large number of fields such as electric vehicles and grid scale energy storage. To ensure the safe and reliable operation of battery systems, it is important to make an accurate and rapid estimation of the state of health (SOH) of Li-ion cells. A Li-ion cell is a complex nonlinear dynamic system. The SOH of a Li-ion can not be measured directly in actual working conditions; it can only be estimated indirectly by external characteristic parameters that reflects the extent of cell aging. It is difficult to ensure the reliability of method based on a single aging feature or model. Therefore, this paper proposes a multi-feature SOH estimation method that combines data-driven XGBoost and a Kalman filter. Firstly, a principal component analysis algorithm to reconstruct multiple battery aging features based on data is used, and an XGBoost online estimation model incorporating multiple features based on the reconstructed feature data is constructed. Finally, the joint optimal estimation of SOH of Li-ion cells by introducing a time-domain Kalman filter based on the real-time correction of the XGBoost model is achieved in this method. The results show that the method improves the accuracy and robustness of the estimation model and achieves a high-precision joint estimation of SOH for Li-ion cells.